Replacing device for trenchless buried plastic pipeline

Abstract

The invention belongs to the technical field of pipeline repair, and discloses a non-excavation type buried plastic pipeline replacement device which comprises a supporting device, a rotating shaft and a pipe breaking device. The supporting device is installed at the front end of the rotating shaft, the pipe breaking device is installed at the rear end of the rotating shaft before construction and penetrates through an old pipe all the time, and the pipe breaking device has the functions of advancing, breaking the old pipe and pulling in a new pipe; when the pipe breaking device advances from a previous excavation area to a next excavation area, a cutter head motor and an advancing motor stop running, a supporting device is detached and placed in the next excavation area, the rotating direction of the advancing motor is reversed, a rotating shaft gradually extends out of a new pipe and leads to the interior of a next old pipe, and the new pipe is cut off. And finally, stopping at the next excavation area and fixing through a supporting device. And the steps are repeated until all the old pipes are broken and replaced with new pipes. The device is compact in structure and high in flexibility, the operation stability of the device is improved, and high cost and construction inconvenience caused by large-area excavation in a traditional method are avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pipeline repair, in particular to a non-excavation buried plastic pipeline replacement device BACKGROUND

[0002] Buried plastic pipelines have a wide range of applications in modern municipal engineering, building water supply and drainage systems, and industrial fluid transportation, and are mainly made of polymeric materials such as polypropylene (PP), high-density polyethylene (HDPE), polyvinyl chloride (PVC), or polybutylene (PB). Although these materials have advantages such as corrosion resistance, light weight, and easy processing, their elastic modulus and bending stiffness are significantly lower than those of traditional metal pipelines (such as steel pipelines) or concrete pipelines, so they are prone to deformation, buckling, and even rupture during construction, long-term use, and maintenance due to external loads (such as soil pressure, traffic dynamic load) or environmental factors (such as temperature changes, chemical corrosion). Especially for old pipelines that have been in service for a long time, the material will undergo molecular chain rupture, embrittlement, and other degradation phenomena due to long-term exposure to ultraviolet radiation, soil electrolyte corrosion, and microbial action, further deteriorating its mechanical properties, and may also cause secondary disasters such as foundation collapse and road subsidence, seriously threatening public safety.

[0003] With the acceleration of urbanization, buried plastic pipelines are increasingly widely used. However, due to the problems of deformation and corrosion of plastic pipelines during long-term use, and the fact that the original size cannot meet the growing demand for use, it is urgent to replace old plastic pipelines. Currently, common pipeline replacement methods mainly include excavation method and non-excavation method, among which the excavation method has a fast construction speed, but causes traffic congestion, destroys green land and gardens, and damages other underground public facilities; the non-excavation method reduces the impact on the ground environment, but requires a large working space during construction and has low construction efficiency.

[0004] The existing non-excavation replacement technology mainly includes pipe breaking method and pipe eating method. The pipe breaking method only needs to excavate a small area, but requires a large force and the installation of a winch, making the construction complex and easily damaging the surrounding environment; the pipe eating method solves the problem of large disturbance to the surrounding soil by the pipe breaking method, but plastic fragments are easily entangled on the cutter disc during the breaking of the plastic pipeline, causing low construction efficiency. In addition, the existing cutting head design is complex, the entire drilling tool needs to be replaced, and blockage easily occurs during cutting, affecting the construction progress.

[0005] Therefore, there is an urgent need for a new buried plastic pipeline replacement device and method that can efficiently complete the pipe replacement task, reduce damage to the surrounding environment, and have strong adaptability and flexibility to solve the problems of low construction efficiency, large environmental impact, and poor universality in the prior art. SUMMARY

[0006] The application provides a device for replacing a non-excavation buried plastic pipeline, which mainly solves the following two technical problems: 1. The existing device for replacing a buried plastic pipeline needs to be excavated in a large area during construction, which is high in construction cost and is not conducive to implementation in places with dense residences and concentrated personnel, thereby affecting the normal maintenance of municipal facilities; 2. The modular design of the existing pulling mechanism and the crushing mechanism is not reasonable enough, lacks flexibility, and limits the application range.

[0007] In order to achieve the above-mentioned application purposes, the application is implemented by the following technical solutions:

[0008] The device for replacing a non-excavation buried plastic pipeline comprises a supporting device, a rotating shaft and a pipe crushing device; the rotating shaft is a rigid long rod with external threads; the supporting device is installed at the front end of the rotating shaft to fix the rotating shaft; the pipe crushing device is installed at the rear end of the rotating shaft before construction, and crushes the old pipe and pulls in the new pipe during the advancing process.

[0009] The pipe crushing device comprises an advancing disc, a first connecting disc, a cutter disc and a second connecting disc which are connected in sequence from front to back and have collinear central axes; the advancing disc is threadedly connected with the rotating shaft, and the first connecting disc, the cutter disc and the second connecting disc are penetrated by the rotating shaft through through holes.

[0010] The advancing disc is driven to rotate by an advancing motor, so as to realize the linear displacement of the advancing disc along the rotating shaft.

[0011] The advancing motor and a pull rod are installed in the first connecting disc; the pull rod is connected with the advancing disc and the cutter disc through gears with bearings at both ends.

[0012] The cutter disc is driven to rotate by a cutter disc motor, so as to realize the pipe crushing function of the cutter disc.

[0013] The cutter disc motor is installed in the second connecting disc, and the second connecting disc is connected with the new pipe through a new pipe connector.

[0014] The advancing disc and the cutter disc rotate at their respective speeds under the driving of the advancing motor and the cutter disc motor, respectively.

[0015] Further, the supporting device comprises a rotating shaft fixing mechanism, a vertical fixing mechanism and a horizontal fixing mechanism; the rotating shaft fixing mechanism has internal threads matched with the rotating shaft, and is used for fixing the rotating shaft; the horizontal fixing mechanism comprises a horizontal support rod, one end of the horizontal support rod is fixed with the rotating shaft fixing mechanism, and the other end is used for being inserted into the bottom soil of the excavation area; the vertical fixing mechanism comprises a vertical support rod, one end of the vertical support rod is fixed with the rotating shaft fixing mechanism, and the other end is used for being inserted into the side soil of the excavation area.

[0016] Further, the outer thread of the rotating shaft is a rectangular thread.

[0017] Further, the advancing wheel disc is provided with an axial through thread hole along the central axis, which is matched with the outer thread of the rotating shaft.

[0018] Further, the rear end surface of the advancing wheel disc is provided with a first internal gear, which is a straight taper internal gear, and the front side inner diameter of the straight taper internal gear is larger than the rear side inner diameter; the output shaft of the advancing motor is connected with a first external gear, which is a straight taper external gear, and the front side inner diameter of the straight taper external gear is larger than the rear side inner diameter; the first external gear and the first internal gear form a straight taper gear transmission in mutual engagement, and the first external gear is clamped in the taper surface of the first internal gear through the taper surface, so that the advancing motor drives the advancing wheel disc to rotate.

[0019] The pull rod comprises a rod body, a second external gear, a first bearing, a third external gear and a second bearing, the rod body is installed inside the first connecting disc, the front end of the rod body is connected with the second external gear through the first bearing, and the rear end of the rod body is connected with the third external gear through the second bearing; the second external gear is a straight taper external gear, and the front side diameter of the straight taper external gear is larger than the rear side diameter; the second external gear and the first internal gear form a straight taper gear transmission in mutual engagement, and the second external gear is clamped in the taper surface of the first internal gear through the taper surface, so that the rotation of the advancing wheel disc drives the second external gear to rotate synchronously.

[0020] The front end surface of the cutter disc is provided with a second internal gear, which is a straight taper external gear, and the front side inner diameter of the straight taper external gear is smaller than the rear side inner diameter; the third external gear and the second internal gear form a straight taper gear transmission in mutual engagement, and the third external gear is clamped in the taper surface of the second internal gear through the taper surface, so that the cutter disc moves linearly along the rotating shaft with the advancing wheel disc.

[0021] Further, the advancing motor and the pull rods are evenly distributed in a ring direction relative to the first internal gear, so that the stress is uniform.

[0022] Further, the rear end surface of the cutter disc is provided with a third internal gear, which is a straight taper external gear, and the front side inner diameter of the straight taper external gear is larger than the rear side inner diameter; the output shaft of the cutter motor is connected with a fourth external gear, which is a straight taper external gear, and the front side inner diameter of the straight taper external gear is larger than the rear side inner diameter; the fourth external gear and the third internal gear form a straight taper gear transmission in mutual engagement, and the fourth external gear is clamped in the taper surface of the third internal gear through the taper surface, so that the cutter motor drives the cutter disc to rotate.

[0023] The fifth external gear adopts straight bevel external gear, the front side diameter of which is larger than the rear side diameter; the fifth external gear and the third internal gear form a straight bevel gear transmission in mutual engagement, and the fifth external gear is clamped in the conical surface of the third internal gear through its conical surface, so as to realize the rotation of the fifth external gear with the cutter head;

[0024] The fifth external gear is connected with the second connecting disc through a bearing.

[0025] Furthermore, the cutter head motor and the plurality of fifth external gears are evenly distributed in a ring direction relative to the third internal gear, so as to make the stress uniform.

[0026] The forward wheel disc is in the overall structure of a circular truncated cone, the front end of which is a smaller diameter end, and the rear end is a larger diameter end.

[0027] Further, the first connecting disc is provided with a blind hole for mounting the forward motor, so as to realize the fixed connection of the forward motor and the first connecting disc; the first connecting disc is provided with a through hole for mounting the pull rod, so as to realize the fixed connection of the pull rod and the first connecting disc.

[0028] Further, the second connecting disc is provided with a blind hole for mounting the cutter head motor, so as to realize the fixed connection of the cutter head motor and the second connecting disc; the second connecting disc is provided with a blind hole for mounting a bearing, so as to realize the fixed connection of the fifth external gear and the second connecting disc through the bearing.

[0029] Further, the second connecting disc is internally provided with a water passing channel, the water passing channel is connected with a water pipe through a water pipe connector, and the water passing channel is communicated with a nozzle; the nozzle is used for spraying water to the side of the cutter head, so that the sprayed water flows out along the gap between the new pipe and the soil layer.

[0030] Further, the forward motor and the cutter head motor can be remotely controlled through a remote control device, respectively.

[0031] Before the whole device is installed, a certain area needs to be excavated in the excavatable area, so as to ensure that the support device, the rotating shaft and the broken pipe device are placed in the specified position. In the subsequent construction process, only a small area of excavation area needs to be excavated at intervals, so as to move the support device on the ground from the previous excavation area to the next excavation area.

[0032] When the pipe breaking device advances from the last excavation area to the next excavation area, the cutter head motor and the advancing motor are first stopped, the support device is removed, the support device is placed in the next excavation area, and the rotating direction of the advancing motor is reversed, the rotating shaft is gradually extended from the inside of the new pipe under the power of the reverse rotation of the advancing disc, and extends into the inside of the next old pipe, and finally stops at the next excavation area and is fixed by the support device.

[0033] This cycle continues until all old pipes are broken and replaced with new pipes.

[0034] The beneficial effects of the present application are:

[0035] (1) The present application adopts a support device combined with the traction of the rotating shaft, combined with the rotation of the advancing disc driven by the advancing motor, to ensure the stability of the pipe breaking device during advancing and pipe breaking, replacing the use of pulling equipment, thereby efficiently completing the pipe replacement task, effectively solving the problem of easy shaking or displacement of the traditional pipe breaking device, and the subsequent excavation only needs to be targeted at the support device, and the small volume of soil excavation reduces the damage to the environment, and does not cause deformation of the soil during implementation, avoiding the high cost and inconvenience of construction caused by the need for large area excavation in the traditional method, and is particularly suitable for densely populated residential areas;

[0036] (2) The present application can be reversed by the advancing motor, so that the rotating shaft smoothly extends from the inside of the new pipe and leads to the inside of the next old pipe, and the support device can also be moved from one excavation area to the next excavation area, cooperating with the cycle operation of the pipe breaking device, so that the entire pipe replacement process can be carried out in an orderly manner, and the construction is more flexible; and also avoids the construction deviation caused by the shaking or displacement of the rotating shaft, and guarantees the construction quality;

[0037] (3) The support device rotating shaft fixing mechanism, vertical fixing mechanism and horizontal fixing mechanism designed in the present application realize stable installation and positioning of the device, effectively solving the problem of device shaking or deviation in the prior art, and improving the safety and reliability in the construction process;

[0038] (4) The present application realizes the synchronous and coordinated movement of each component in the pipe breaking device through the connection design of the advancing disc, the pull rod, the connecting disc and the cutter head in the pipe breaking device, realizes accurate breaking and positioning of the old pipe, improves the practical flexibility of the device, guarantees the stable transmission between each component, avoids the tilting or jamming phenomenon caused by uneven stress, and further guarantees the safety of construction;

[0039] (v) The present invention, through the connection structure between the second connecting disc and the new pipe connector, can flexibly select the appropriate connector according to the size of the new pipe, and has strong versatility; whether it is the need to replace new pipes with different diameters or when there are certain differences in the diameter of the old pipe, a suitable new pipe connector can be quickly found for installation, without the need to customize a whole set of equipment for different projects, reducing equipment costs and construction costs, and expanding the application scope of the device of the present invention.

[0040] (vi) The present invention has a water passage and a nozzle in the pipe breaking device. It can be connected to the water pipe through the water pipe connector, which provides an auxiliary water spraying function during the construction process, so as to wash the cutter head and the soil to be cut. The resulting broken pipe and flowing soil will flow outward along the gap between the new pipe and the soil layer, which effectively reduces the difficulty of cutting the old pipe and the soil, and at the same time reduces the friction of the new pipe movement, which is conducive to the smooth installation of the new pipe. Attached Figure Description

[0041] To more clearly illustrate the specific embodiments of the present invention and the prior art, the accompanying drawings used in the description of the specific embodiments will be introduced below, wherein:

[0042] Figure 1 This is a schematic diagram of the replacement device of the present invention;

[0043] Figure 2 This is a schematic diagram of the fixed rotating shaft device in the replacement device of the present invention;

[0044] Figure 3 This is a schematic diagram of the pipe-crushing device in the replacement apparatus of the present invention;

[0045] Figure 4 for Figure 3 A schematic diagram of the forward wheel in the diagram;

[0046] Figure 5 for Figure 3 A schematic diagram of the tie rod in the diagram;

[0047] Figure 6 for Figure 5 A schematic diagram of the structure of the second external gear and the first bearing;

[0048] Figure 7 for Figure 3 A schematic diagram of the cutter head in the diagram.

[0049] In the above diagram: 1. Excavation area; 2. Support device; 21. Rotary shaft fixing mechanism; 22. Vertical fixing mechanism; 23. Horizontal fixing mechanism; 3. Old pipe; 4. Rotary shaft; 5. Pipe crushing device; 51. Forward wheel; 511. Forward wheel thread; 512. First internal gear; 52. Forward motor; 53. Tie rod; 531. Second external gear; 532. First bearing; 533. Rod body; 534. Third external gear; 535. Second bearing; 54. First connecting disc; 55. Cutterhead; 551. Pipe crushing blade; 552. Rotary shaft through hole; 553. Cutterhead right thread; 56. Cutterhead motor; 57. Fifth external gear; 58. Second connecting disc; 6. New pipe connector; 7. New pipe; 8. Water pipe connector; 9. Water pipe; 10. Nozzle. Detailed Implementation

[0050] To further understand the invention's content, features, and effects, the following embodiments are provided, along with detailed descriptions in conjunction with the accompanying drawings:

[0051] like Figure 1 As shown, this embodiment provides a trenchless buried plastic pipe replacement device, including a support device 2, a rotating shaft 4, and a pipe-crushing device 5. The support device 2 is installed at the front end of the rotating shaft 4, and the rotating shaft 4 cannot move or rotate under the fixation of the support device 2. The pipe-crushing device 5 is installed at the rear end of the rotating shaft 4 before construction and runs through the old pipe 3. The functions of the pipe-crushing device 5 are to advance, crush the old pipe 3, and pull in the new pipe 7.

[0052] Generally, the replacement device of the present invention is suitable for large-diameter drainage pipes, that is, the diameter of the buried plastic pipe (old pipe 3) to be replaced is not less than 300mm, and the pipe design slope is not greater than 1.5%.

[0053] In the description of this invention, all components are defined as front end or front side in the direction of advance toward the pipe crushing device 5, and as rear end or rear side in the direction of advance away from the pipe crushing device 5.

[0054] The rotating shaft 4 is a long steel rod with external threads, preferably rectangular threads. The rotating shaft 4 bears tensile force during the forward movement of the pipe crushing device 5 and has good tensile strength.

[0055] Before installation, a certain area needs to be excavated in the excavable area to ensure that the support device 2, the rotating shaft 4, and the pipe-breaking device 5 are all placed in their designated positions. During subsequent construction, only smaller excavation areas 1 need to be excavated at intervals to move the support device 2 from one excavation area to the next on the ground.

[0056] like Figure 2As shown, the support device 2 includes a rotating shaft fixing mechanism 21, a vertical fixing mechanism 22 and a horizontal fixing mechanism 24. The rotating shaft fixing mechanism 21 is provided with an internal thread matched with the rotating shaft 4, and in the working state, the rotating shaft fixing mechanism 21 is screwed with the rotating shaft 4 to fix the rotating shaft 4. The horizontal fixing device 24 is composed of three horizontal support rods, one end of each horizontal support rod is fixed with the rotating shaft fixing mechanism 21, and the other end is inserted into the ground soil of the excavation area, the three horizontal support rods form an angle of 60°-90° with each other, forming a tripod support, so as to ensure the horizontality of the rotating shaft 4 in the working state. The vertical fixing device 22 is composed of 3-4 vertical support rods, one end of each vertical support rod is fixed with the rotating shaft fixing mechanism 21, and the other end is inserted into the soil around the excavation area 1, and each vertical support rod forms an angle of 45°-60° with the side of the soil, and the vertical support rods are uniformly distributed around the soil of the excavation area 1 to support and bear the horizontal tension of the device in the working state.

[0057] As shown in the figure, Figure 3 The broken pipe device 5 includes an advancing disc 51, an advancing motor 52, a pull rod 53, a first connecting disc 54, a cutter disc 55, a cutter disc motor 56, a first external gear 57, and a second connecting disc 58. The central axes of the advancing disc 51, the first connecting disc 54, the cutter disc 55, and the second connecting disc 58 are collinear.

[0058] As shown in the figure, Figure 4 The advancing disc 51 has a circular truncated cone structure, with a smaller diameter end at the front end and a larger diameter end at the rear end. An axial through-thread hole 511 is formed in the advancing disc 51 along the central axis, which is matched with the external thread of the rotating shaft 4, so that the rotating shaft 4 passes through the advancing disc 51 and is threadedly connected with the advancing disc 51. At the same time, the thread connection ensures that the broken pipe device 5 does not shake during movement.

[0059] A first internal gear 512 is arranged on the rear end surface of the advancing disc 51, and the first internal gear 512 is collinear with the central axis of the advancing disc 51. The first internal gear 512 is a straight conical internal gear, and the inner diameter of the front side is larger than that of the rear side (i.e., the diameter of the internal gear gradually increases from the inner hole to the outer edge).

[0060] In the description of the present application, the straight conical internal gear refers to the teeth of the gear distributed on the internal surface of the circular cone, and the tooth profile generatrix of the gear is a straight line. The straight conical external gear refers to the teeth of the gear distributed on the external surface of the circular cone, and the tooth profile generatrix of the gear is a straight line.

[0061] The advancing wheel disc 51 is connected with the cutter disc 55 through the first connecting disc 54. The first connecting disc 54 is provided with a central through hole along a central axis thereof, and the central through hole is used for allowing the rotating shaft 4 to pass through. The central through hole is provided with mounting holes for mounting the advancing motor 52 and the pull rod 53. The mounting hole of the advancing motor 52 is a blind hole, and the advancing motor 52 is fixedly connected with the first connecting disc 54 in a close fit manner. The mounting hole of the pull rod 53 is a through hole, and the rod body 533 of the pull rod 53 is fixedly connected with the first connecting disc 54 in a close fit manner.

[0062] The advancing motor 52 can rotate in both forward and reverse directions, and is coaxially arranged on the front side of the first connecting disc 54 together with the advancing wheel disc 51, the first connecting disc 54 and the cutter disc 55. The output shaft of the advancing motor 52 is connected with a first external gear, and the first external gear is a straight taper external gear, and the inner diameter of the front side of the first external gear is larger than that of the rear side (i.e., the diameter of the external gear gradually decreases from the front end to the rear end). The first external gear connected with the advancing motor 52 and the first internal gear 512 of the advancing wheel disc 51 form a straight taper gear transmission in a meshing manner, and the first external gear is clamped in the taper surface of the first internal gear 512 through the taper surface thereof. Thus, the advancing motor 52 drives the advancing wheel disc 51 to rotate, so that the advancing wheel disc 51 moves linearly along the axial direction of the rotating shaft 4. Since the advancing motor 52 is embedded in the first connecting disc 54, only the rotating rod of the advancing motor 52 extends to the outside of the first connecting disc 54, and the rest of the advancing motor 52 is wrapped by the first connecting disc 54 to form an integral whole. The advancing motor 52 will not be pulled out during the advancing of the advancing wheel disc 51.

[0063] The advancing motor 52 and the two to four pull rods 53 are evenly distributed in a ring shape in the first connecting disc 54, so as to ensure uniform stress distribution. The pull rod 53 is coaxially arranged with the advancing wheel disc 51, the first connecting disc 54 and the cutter disc 55.

[0064] As shown in Figure 5 and Figure 6 , the pull rod 53 includes a rod body 533, a second external gear 531, a first bearing 532, a third external gear 534 and a second bearing 535.

[0065] The rod 533 is installed inside the first connecting disc 54. One end of the rod 533 is connected to the second external gear 531 via the first bearing 532, and the other end is fixedly connected to the third external gear 534 via the second bearing 535. The second external gear 531, the first bearing 532, the third external gear 534, and the second bearing 535 are all located outside the first connecting disc 54. The second external gear 531 is a straight bevel gear, with its front diameter larger than its rear diameter. The second external gear 531 and the first internal gear 512 of the forward wheel 51 form a meshing straight bevel gear transmission. The second external gear 531 is engaged within the conical surface of the first internal gear 512 through its conical surface, enabling the rotation of the forward wheel 51 to drive the second external gear 531 to rotate synchronously. During the movement of the pipe crushing device 5, the second external gear 531 and the forward wheel 51 remain meshed at all times, thus the pull rod 53 also remains connected to the forward wheel 51 at all times.

[0066] like Figure 7 As shown, the cutter head 55 includes a pipe-crushing blade 551, a rotating shaft through hole 552, a second internal gear, and a third internal gear 553. The pipe-crushing blade 551 is arranged circumferentially on the cutter head 55 and is used to crush the old pipe 3 by the movement of the cutter head 55. The cutter head 55 has a centrally penetrating rotating shaft through hole 552 along its central axis, which is used for the rotating shaft 4 to pass through. The second internal gear is provided on the front end face of the cutter head 55, and the third internal gear 553 is provided on the rear end face. Both the second and third internal gears 553 are collinear with the central axis of the cutter head 55. The second internal gear is a straight bevel internal gear, and its front inner diameter is smaller than its rear inner diameter (i.e., the diameter of the internal gear gradually increases from the inner hole to the outer edge). The third external gear 534 of the pull rod 53 and the second internal gear of the cutter head 55 form a meshing bevel gear transmission. The third external gear 534 is engaged within the bevel surface of the second internal gear, thus enabling the cutter head 55 to move linearly along the rotating shaft 4 with the forward wheel 51. Due to the function of the bearing 532, the second external gear 531 and the third external gear 534 can rotate at their respective speeds, thereby ensuring that the forward wheel 51 and the cutter head 55 rotate with their respective powers, and the first connecting disc 54 in the middle does not rotate. The third internal gear 553 is a bevel internal gear, and its front inner diameter is larger than its rear inner diameter (i.e., the diameter of the internal gear gradually increases from the inner hole to the outer edge).

[0067] The second connecting disc 58 is connected to the rear side of the cutter head 55, and the second connecting disc 58 is connected to the new pipe 7 through the new pipe connector 6. The second connecting disc 58 has a central through hole along its central axis, which is used for the rotating shaft 4 to pass through. The second connecting disc 58 is also provided with a mounting hole for mounting the cutter head motor 56. This mounting hole is a blind hole, which can achieve a tight fit between the cutter head motor 56 and the second connecting disc 58.

[0068] The cutter head motor 56 is installed on the front side of the second connecting disc 58, and the cutter head motor 56 is coaxially arranged with the cutter head 55 and the second connecting disc 58. The output shaft of the cutter head motor 56 is connected with a fourth external gear, which is a straight taper external gear, and the inner diameter of the front side of the fourth external gear is larger than that of the rear side (that is, the diameter of the external gear gradually decreases from the front end to the rear end). The fourth external gear connected with the cutter head motor 56 and the third internal gear 553 of the cutter head 55 form a straight bevel gear transmission, and the fourth external gear is clamped in the taper surface of the third internal gear 553 through the taper surface, so as to realize the rotation of the cutter head 55 driven by the cutter head motor 56.

[0069] The fifth external gear 57 is installed on the front side of the second connecting disc 58 and coaxially arranged with the second connecting disc 58. The fifth external gear 57 is a straight taper external gear, and the diameter of the front side of the straight taper external gear is larger than that of the rear side. The fifth external gear 57 and the third internal gear 553 of the cutter head 55 form a straight bevel gear transmission, and the fifth external gear 57 is clamped in the taper surface of the third internal gear 553 through the taper surface, so as to realize the rotation of the fifth external gear 57 along with the cutter head 55.

[0070] The fifth external gear 57 and the fourth external gear of the cutter head motor 56 are evenly distributed on the third internal gear 553, which ensures uniform stress. The fifth external gear 57 is connected with the second connecting disc 58 through a bearing, the bearing is embedded and installed on the end face of the second connecting disc 58, and the bearing is connected with the fifth external gear 57. Through the connection of the cutter head motor 56 and the fifth external gear 57, the second connecting disc 58 moves linearly along the rotation shaft 4 with the cutter head 55.

[0071] The rear side of the second connecting disc 58 is connected with the new pipe 7 through the new pipe connector 6. The new pipe connector 6 can be selected according to the size of the new pipe 7, and is suitable for all sizes larger than the old pipe 3 and smaller than the diameter of the cutter head 55.

[0072] As a preferred embodiment, the second connecting disc 58 further comprises a water passing channel, the water passing channel is connected with a water pipe 9 through a water pipe connector 8, and the water passing channel is communicated with a nozzle 10. The water pipe 9 can be placed in the new pipe 7 to supply water to the nozzle 10. The nozzle 59 is arranged in the middle of the second connecting disc 58 and faces the pipe crushing blade 551, which is used to spray water to the pipe crushing blade 551. The sprayed water flows out along the gap between the new pipe 7 and the soil layer, thereby reducing the difficulty of cutting the old pipe and the soil body and reducing the friction of the new pipe movement.

[0073] The forward motor 52 and the cutter head motor 56 can be used separately through a remote control device, and such remote control and flexible control reduces the complexity and danger of manual on-site operation, and further improves the construction efficiency.

[0074] When the pipe breaking device 5 advances from the last excavation area to the next excavation area, the cutter motor 56 and the advancing motor 52 are first stopped, the supporting device 2 is removed, the supporting device 2 is placed in the next excavation area, the rotating direction of the advancing motor 52 is reversed, the rotating shaft 4 is gradually extended from the inside of the new pipe 7 under the power of the reverse rotation of the advancing disc 51, and is always extended into the inside of the next section of the old pipe 3, and finally stops at the next excavation area and is fixed by the supporting device 2. This cycle is repeated until all the old pipes 3 are broken and replaced by the new pipes 7.

[0075] Although the preferred embodiments of the present application are described above in conjunction with the drawings, the present application is not limited to the above specific embodiments, and the above specific embodiments are merely illustrative and not restrictive. Those skilled in the art can make many specific changes to the present application under the guidance of the present application without departing from the purpose of the present application and the scope protected by the claims, and these are all within the scope of protection of the present application.

Claims

1. A replacement device for trenchless buried plastic pipes, characterized in that, It includes a support device, a rotating shaft, and a pipe-crushing device; the rotating shaft is a rigid long rod with external threads; the support device is installed at the front end of the rotating shaft to fix the rotating shaft; the pipe-crushing device is installed at the rear end of the rotating shaft before construction, and crushes the old pipe and pulls in the new pipe during the forward movement. The tube crushing device includes a forward wheel, a first connecting disc, a cutter disc, and a second connecting disc connected sequentially from front to back and with their central axes collinear; the forward wheel is threadedly connected to the rotating shaft, and the rotating shaft passes through the first connecting disc, the cutter disc, and the second connecting disc through a through hole. The forward motor drives the forward wheel to rotate, thereby enabling the forward wheel to perform linear displacement along the axis of rotation. The forward motor and the pull rod are installed inside the first connecting disc; the pull rod is connected to the forward wheel and the cutter head respectively through gears with bearings at both ends; The cutter head is driven to rotate by a cutter head motor, thereby realizing the tube crushing function of the cutter head; The cutter head motor is installed inside the second connecting disc, and the second connecting disc is connected to the new pipe through a new pipe connector; The forward wheel and the cutter head rotate at their respective speeds under the drive of the forward motor and the cutter head motor, respectively.

2. The replacement device for a trenchless buried plastic pipe according to claim 1, characterized in that, The support device includes a rotating shaft fixing mechanism, a vertical fixing mechanism, and a horizontal fixing mechanism; the rotating shaft fixing mechanism has an internal thread that matches the rotating shaft for fixing the rotating shaft; the horizontal fixing mechanism includes a horizontal support rod, one end of which is fixed to the rotating shaft fixing mechanism, and the other end of which is used to insert into the bottom soil of the excavation area; the vertical fixing device includes a vertical support rod, one end of which is fixed to the rotating shaft fixing mechanism, and the other end of which is used to insert into the side soil of the excavation area.

3. The replacement device for a trenchless buried plastic pipe according to claim 1, characterized in that, The rear end face of the forward wheel is provided with a first internal gear, which is a straight bevel internal gear, and the front inner diameter of the straight bevel internal gear is larger than the rear inner diameter; the output shaft of the forward motor is connected to a first external gear, which is a straight bevel external gear, and the front inner diameter of the straight bevel external gear is larger than the rear inner diameter; The first external gear and the first internal gear form a meshing straight bevel gear transmission, and the first external gear is engaged within the bevel surface of the first internal gear through its conical surface, thereby enabling the forward motor to drive the forward wheel to rotate. The pull rod includes a rod body with a collinear central axis, a second external gear, a first bearing, a third external gear, and a second bearing. The rod body is installed inside the first connecting disc. The front end of the rod body is connected to the second external gear through the first bearing, and the rear end is connected to the third external gear through the second bearing. The second external gear is a bevel gear, with its front diameter larger than its rear diameter. The second external gear and the first internal gear form a meshing bevel gear transmission, and the second external gear is engaged within the bevel surface of the first internal gear through its conical surface, thereby enabling the rotation of the forward wheel to drive the second external gear to rotate synchronously. The front end face of the cutter head is provided with a second internal gear, which is a straight bevel external gear with a front inner diameter smaller than a rear inner diameter. The third external gear and the second internal gear form a meshing straight bevel gear transmission, and the third external gear is locked within the conical surface of the second internal gear through its conical surface, so that the cutter head can move linearly along the axis of rotation with the forward wheel.

4. The replacement device for a trenchless buried plastic pipe according to claim 3, characterized in that, The forward motor and several of the pull rods are evenly distributed in a circumferential manner relative to the first internal gear to ensure uniform force distribution.

5. The replacement device for a trenchless buried plastic pipe according to claim 1, characterized in that, A third internal gear is provided on the rear end face of the cutter head. The third internal gear is a straight bevel external gear, and the front inner diameter of the straight bevel external gear is larger than the rear inner diameter. The output shaft of the cutter head motor is connected to a fourth external gear, which is also a straight bevel external gear, and its front inner diameter is larger than its rear inner diameter. The fourth external gear and the third internal gear form a meshing straight bevel gear transmission, and the fourth external gear is engaged within the conical surface of the third internal gear through its conical surface, thereby enabling the cutter head motor to drive the cutter head to rotate. The fifth external gear is a straight bevel external gear, with the front diameter being larger than the rear diameter. The fifth external gear and the third internal gear form a meshing straight bevel gear transmission, and the fifth external gear is engaged within the conical surface of the third internal gear through its conical surface, thereby enabling the fifth external gear to rotate together with the cutter head. The fifth external gear is connected to the second connecting disk via a bearing.

6. The replacement device for a trenchless buried plastic pipe according to claim 5, characterized in that, The cutter head motor and several of the fifth external gears are evenly distributed in a circumferential manner relative to the third internal gear to ensure uniform force distribution.

7. The replacement device for a trenchless buried plastic pipe according to claim 1, characterized in that, The first connecting disc is provided with a blind hole for installing the forward motor, thereby achieving a fixed connection between the forward motor and the first connecting disc; the first connecting disc is provided with a through hole for installing the pull rod, thereby achieving a fixed connection between the pull rod and the first connecting disc.

8. The replacement device for a trenchless buried plastic pipe according to claim 1, characterized in that, The second connecting disc is provided with a blind hole for installing the cutter head motor, so as to achieve a fixed connection between the cutter head motor and the second connecting disc; the second connecting disc is provided with a blind hole for installing a bearing, so as to achieve a fixed connection between the fifth external gear and the second connecting disc through the bearing.

9. A replacement device for a trenchless buried plastic pipe according to claim 1, characterized in that, The second connecting disc has a water passage inside, which is connected to a water pipe via a water pipe connector and is also connected to a nozzle. The nozzle is used to spray water onto the periphery of the cutterhead, so that the sprayed water flows out along the gap between the new pipe and the soil layer.

10. A replacement device for a trenchless buried plastic pipe according to claim 1, characterized in that, The forward motor and the cutter head motor can be remotely controlled separately via a remote control device.

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